With audiences confused, producers livid and picket lines erected, the drama spilled out on to the street where famous actors with a night off signed autographs, musicians put on an impromptu concert and union representatives paraded a giant inflatable rat.

The strike over the use of recorded music has shut down 18 musicals, from Hairspray and Mamma Mia to Aida and Les Misérables. Only Cabaret, playing at Studio 54 which has a separate contract with the musicians' union, was still showing by Friday night.

"It's a real disappointment," said Carol Sikolsky from Chicago, who had been hoping to see 42nd Street. "This is the first time I've been to New York in 12 years and when you come to New York you want to see a show. That's the whole point."

A few were supportive of the strikers. "I can see why they'd do it if it's going to protect their jobs, particularly in these times, and I certainly don't like the idea of canned music," said Jeb Hanning from Florida.

But even he could scarcely mask his annoyance at being denied the chance to see La Bohème. "I don't know when I'll be back here again and I can't see it coming to Tampa."

The strike is over the minimum number of musicians a theatre has to employ while staging a musical. The contract, which expired last Sunday, requires anything from three to 36 musicians depending on the size and history of the theatre.

Excess

Producers want to abolish the minimums altogether, claiming they are forced to employ musicians they do not need and sometimes even pay people not to play just to make up the numbers.

Musicians argue that the minimums both protect jobs and the quality of live music on Broadway which would otherwise be replaced by recordings.

Both sides were apparently taken aback by the speed at which the dispute escalated on Friday night, when all the musicals were called off. The musicians expected the producers to compromise. The producers, who had planned to use computer-generated music for the duration of the dispute, did not expect the actors and stagehands to respect the picket lines. The last time Broadway shut down was in 1975, over the same issue. The strike lasted three weeks. Theatres also closed on September 11 and 12 2001, following the terrorist attacks.

"No one saw this happening,"one producer told the New York Times. "All the producers believed the [stage hands] were taken care of."

By Friday night, with no agreement in sight, the producers decided to cancel the shows, leaving the strikers out in the cold warming up their hands on take-away coffee and yelling derisive remarks about virtual orchestras and karaoke on Broadway.

On Saturday night they played a minor-key funeral dirge entitled "Broadway Death March" by the stands where people were waiting for last minute tickets.

With their tickets now worthless some gave up and waited for refunds while others opted for straight plays, filling what vacant seats were left in Russel Simmons' Def Poetry Jam and giving a lift to Ma Rainey's Black Bottom starring Whoopi Goldberg. Some were just finishing their dessert when they heard the news.

"Dinner was fine till the waitress told us our show was cancelled," said Neil Mandell, who had come in for the night from Pennsylvania on Friday with his wife, Sharan, to see some shows.

His wife agreed: "We weren't thrilled" about the prospect of a virtual orchestra, she told the New York Times. "But now we're devastated."

Support from the actors will be crucial in their hope of both forcing a compromise from the producers and winning over public opinion. On Friday the Equity branch gave them near-unanimous support.

"To put it very simply, singing a capella can only get you so far," joked Christine Ebersole, who won the 2001 Tony for best actress for her performance in 42nd Street. "We need to stand together in this. Unfortunately, corporations don't understand art. It's not their job. They don't understand that live music is the backbone of musical theatre. Without it Broadway will turn into a Disney theme park," she added.

"Nobody likes the idea of a plastic Broadway," said Joel Grey, who won an Oscar for best supporting actor for his 1972 performance in the film version of Cabaret and is now appearing in Chicago. "The idea of canned and electronic music in a Broadway show is totally unacceptable."

Compromise

Yesterday both sides remained entrenched, blaming each other for walking away from a compromise. "We have no negotiating partner," said Jed Bernstein, president of the League of American Theatres, the national trade organisation for the commercial theatres. "In order to resolve this you have to have someone across the table to negotiate with, but they are essentially saying: 'We know what an orchestra is, and it's our way or the highway'."

The union similarly suggested that it was the employers who were refusing to compromise. "We came back up here willing to negotiate," said Bill Moriarity, the president of the musicians' union Local 802, which is part of the American Federation of Musicians. "And we find they have for all intents and purposes left the building. We're not anywhere near where we need to be to ratify something."

But while both sides dug in over the weekend city officials expressed concern about the possible financial impact on New York, which is already suffering a huge budget deficit and struggling with the fallout from September 11.

Broadway is one of New York's most famous tourist attractions. Last season it drew about 11 million visitors, who spent $643m (£400m) just on tickets. Add the pre-theatre meals, hotels, cabs and other spending and, according to the mayor's office, the figure jumps to $4.4bn, supporting more than 40,000 jobs.

"The last thing this economy needs is a Broadway strike," said New York mayor Michael Bloomberg in his weekly radio show on Friday. "People come here for the cultural institutions. Broadway is not just a significant part of it, it's the most visible part of it."

While musicians acknowledge the short term inconvenience they believe that if the producers win it will have a lasting, detrimental impact on Broadway's reputation. "Virtual theatre doesn't cost $100 a night," said Gordon Titcomb, 50, who plays banjo and steel guitar for Urban Cowboy, which is in preview and scheduled to open on March 27, and may well be delayed if the strike continues. "It costs $26 a month and it's called cable TV."